ISO/TR 23583

• Abstract:

  This document specifies the assessment of copper winding sulfur corrosion in power equipment. It is applicable to the sulfur corrosion resistance testing of copper windings in newly installed and in-service power equipment.

• Status: Not Published
• ICS: 27.010 - Energy and heat transfer engineering in general
• ICS: 77.060 - Corrosion of metals
• Technical Committee: ISO/TC 156 - Corrosion of metals and alloys
• Drafting Committee: ISO/TC 156/WG 9 - Corrosion testing of materials for power generation
• Current Stage: 6000 - International Standard under publication
• Start Date: 08-Jul-2026
• Completion Date: 24-Oct-2026

ISO/TR 23583 is an ISO Technical Report on a sulfur corrosion test method for copper winding in electric field for power equipment. It specifies how to prepare the winding specimen, how to set up and run the test, and how to judge sulfur corrosion resistance for newly installed and in-service power equipment.

What does ISO/TR 23583 specify?

ISO/TR 23583 specifies a test method for assessing sulfur corrosion of copper windings used in power equipment. The document is organized into clauses on scope, terms, general regulation, specimen preparation, instruments and equipment, test preparation, test procedures, and evaluation, followed by a bibliography.

The method is built around a pig-tail model made from copper winding and insulating paper, which is then exposed to oil containing corrosive sulfur under controlled temperature and electric field conditions. In practice, that means the test is meant to reflect how the winding behaves in oil-filled equipment rather than only in a simple laboratory corrosion test.

What are the key requirements of ISO/TR 23583?

Clause 4 sets the basic test concept: prepare a pig-tail specimen, immerse it in oil containing corrosive sulfides, apply a specified temperature and electric field strength, then assess corrosion both visually and by measuring copper in the insulating oil. This matters because the document ties the result to both surface damage and dissolved copper, not to one indicator alone.

Specimen materials and assembly

Clause 5.1 uses transformer copper windings conforming to GB/T 6451, and Clause 5.3 uses transformer insulating paper conforming to GB/T 6451. Clause 5.2 uses insulating oil conforming to IEC 60296, and Clause 5.4 introduces dibenzyl disulfide (DBDS) as the sulfur compound used in the test oil. In practice, the test depends on using the specified winding, paper, oil, and sulfur source so the result is comparable.

Test equipment

Clause 6 lists the required equipment: a thermostatic oil tank, a vacuum drying immersion oil tank, an electric heating experimental tank, a DC/AC power supply, and a plasma coupled atomic emission spectrometer. This gives the reader the full equipment set needed to prepare the specimen, simulate operating conditions, and measure copper content.

Test preparation

Clause 7.1 forms the paper-wrapped winding into a pig-tail model to prevent discharge during pressurization. Clause 7.2 dries the specimen in vacuum, and Clause 7.3 immerses it in degassed insulating oil with DBDS, then removes air with nitrogen before the specimen is kept immersed under controlled conditions. In practice, these steps remove moisture and air so the corrosion test focuses on the oil and electric field effects.

Test procedure

Clause 8.1 heats the specimen, connects it to a DC or AC power source, and applies the test electric field for a minimum duration. Clause 8.2 requires cooling to room temperature before the winding is removed. This sequence matters because the specimen is judged after exposure under hot, energized conditions similar to service.

Evaluation

Clause 9.1 provides qualitative evaluation from the macroscopic corrosion morphology of the copper winding, with reference to ASTM D 1275B. Clauses 9.2 and 9.3 use copper content in the insulating oil, measured by ICP-AES, to classify resistance into levels from excellent to poor. In practice, users get both a visual corrosion check and a quantitative severity grade.

What terms does ISO/TR 23583 define?

• Copper content - the mass fraction of substances determined by the procedure in this document, expressed in mg/kg.
• Corrosive sulfur - elemental sulfur or thermally unstable sulfides in insulating oils for electrical equipment that can corrode metals such as copper and silver.
• Sulfur corrosion resistance - the ability to resist corrosive sulfur corrosion under specified conditions.
• Pig-tail model - the bent and wrapped copper winding specimen used to prevent discharge during pressurization and testing.
• Dibenzyl disulfide (DBDS) - the sulfur-containing additive used to create the corrosive oil condition in the test.
• Inductively coupled plasma atomic emission spectroscopy (ICP-AES) - the analytical method used to determine copper content in the insulating oil.

Who uses ISO/TR 23583?

ISO/TR 23583 is used by power equipment manufacturers, test laboratories, and maintenance or inspection teams that need to evaluate copper winding behavior in oil-filled equipment. It is also relevant to quality managers and buyers who compare winding materials, insulation systems, and oil compatibility for newly installed or in-service assets.

Which standards are used with ISO/TR 23583?

The document cites related standards that provide materials, methods, or context:

• GB/T 6451 - used for the copper winding and insulating paper material definitions.
• IEC 60296 - used for the insulating oil specification.
• ASTM D 1275A and ASTM D 1275B - cited as related corrosive sulfur test methods for insulating oils, with ASTM D 1275B used for qualitative comparison.
• IEC 62535 - a related method for detecting potentially corrosive sulphur in insulating oil.
• GB/T 25961 - another related test method for corrosive sulfur in insulating oils.
• GB/T 38265.15, ASTM D 130, and ISO 6251 - cited as related copper corrosion test methods in other fields.

What does the ISO/TR 23583 document contain?

ISO/TR 23583 contains one material table for insulating oil properties, three figures showing the pig-tail model and test tank arrangements, and a step-by-step test method. It gives the specimen preparation details, the required apparatus, the immersion and gas-purging setup, and the heating and cooling procedure. It also includes both qualitative and quantitative evaluation routes, so users can check appearance and measure copper in oil. The bibliography places the method in context with insulating-oil corrosion and copper-corrosion standards used elsewhere.

FINAL DRAFT
Technical
Report
ISO/DTR 23583
ISO/TC 156
Sulfur corrosion test method of
Secretariat: SAC
copper winding in electric field for
Voting begins on:
power equipment
2026-05-12
Voting terminates on:
2026-07-07
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
ISO/DTR 23583:2026(en) © ISO 2026

FINAL DRAFT
ISO/DTR 23583:2026(en)
Technical
Report
ISO/DTR 23583
ISO/TC 156
Sulfur corrosion test method of
Secretariat: SAC
copper winding in electric field for
Voting begins on:
power equipment
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland Reference number
ISO/DTR 23583:2026(en) © ISO 2026

ii
ISO/DTR 23583:2026(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General regulation . 1
5 Specimen preparation . . 2
5.1 Copper winding .2
5.2 Insulating oil .2
5.3 Insulating paper .2
5.4 Dibenzyl disulfide .2
6 Instruments and equipment . 2
6.1 Thermostatic oil tank .2
6.2 Vacuum drying immersion oil tank .3
6.3 Electric heating experimental tank .3
6.4 DC/AC power supply .4
6.5 Plasma coupled atomic emission spectrometer.4
7 Preparation of test . 4
7.1 Establishing a pig-tail model .4
7.2 Drying treatment.4
7.3 Immersion oil .4
8 Test procedures . 5
8.1 Heating.5
8.2 Remove the sample after cooling .6
9 Evaluation of oil sulfur corrosion resistance performance . 6
9.1 Qualitative evaluation .6
9.2 Quantitative evaluation .6
9.3 Quantitative evaluation .6
Bibliography . 7

iii
ISO/DTR 23583:2026(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/DTR 23583:2026(en)
Introduction
Many factors affect the sulfur corrosion of copper windings in power equipment in the power industry.
These include:
— temperature;
— corrosive sulfide concentration in oil;
— acid products derived from oil-paper insulation aging;
— moisture;
— the type of electric field (AC or DC electric field);
— electric field strength;
— the contact state between the copper winding and the insulating paper;
— the quality of the copper winding.
These have a significant influence on the occurrence of sulfur corrosion and the generation of corrosion
products. The current assessment methods of sulfur corrosion of copper windings do not sufficiently
consider these factors. Existing standards (e.g. ASTM D 1275A, ASTM D 1275B, IEC 62535, GB/T 25961) test
specifications or methods for testing whether the quality of insulating oil meets the requirements.
As for the corrosion of copper, the existing standards are test methods for the co
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ISO #####-#:####(X/DTR 23583:(en) Formatted: Font: 11 pt, Bold
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at the address below or ISO’s member body in the country of the requester.
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ISO copyright office
from edge: 0.5 cm
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
Formatted: French (Switzerland)
EmailE-mail: [e-mail]
Formatted: French (Switzerland)
Website: www.iso.orgwww.iso.org
Formatted: French (Switzerland)
Published in Switzerland
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pt, Line spacing: single
ii © ISO #### 2026 – All rights reserved
ii
ISO/DTR 23583:(en)
Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold, English (United Kingdom)
Formatted: Font: 11 pt, Bold
Contents
Formatted: HeaderCentered, Left, Space After: 0 pt,
Line spacing: single
Foreword . v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General regulation . 1
5 Specimen preparation . 2
5.1 Copper winding . 2
5.2 Insulating oil . 2
5.3 Insulating paper . 2
5.4 Dibenzyl disulfide . 2
6 Instruments and equipment . 2
6.1 Thermostatic oil tank . 2
6.2 Vacuum drying immersion oil tank . 3
6.3 Electric heating experimental tank . 3
6.4 DC/AC power supply . 4
6.5 Plasma coupled atomic emission spectrometer . 4
7 Preparation of test . 4
7.1 Establishing a pig-tail model . 4
7.2 Drying treatment . 4
7.3 Immersion oil . 5
8 Test procedures . 7
8.1 Heating . 7
8.2 Remove the sample after cooling . 7
9 Evaluation of oil sulfur corrosion resistance performance . 7
9.1 Qualitative evaluation . 7
9.2 Quantitative evaluation . 7
9.3 Quantitative evaluation . 7
Bibliography . 9

Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General regulation . 1
5 Specimen preparation . 2
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5.1 Copper winding . 2
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5.2 Insulating oil . 2
5.3 Insulating paper . 2 Formatted: FooterCentered, Left, Line spacing: single
5.4 Dibenzyl disulfide . 2
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6 Instruments and equipment . 2
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6.1 Thermostatic oil tank . 2
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© ISO TR 23583 2026 – All rights reserved
iii
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6.2 Vacuum drying immersion oil tank. 2
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6.3 Electric heating experimental tank . 2
6.4 DC/AC power supply. 3
6.5 Plasma coupled atomic emission spectrometer . 3
7 Preparation of test . 3
7.1 Establish a pig-tail model . 3
7.2 Drying treatment . 4
7.3 Immersion oil . 4
8 Test procedures . 5
8.1 Heating . 5
8.2 Remove the sample after cooling . 5
9 Evaluation of oil sulfur corrosion resistance performance . 5
9.1 Qualitative evaluation . 5
9.2 Quantitative evaluation . 5
9.3 Quantitative evaluation . 5
Bibliography . 错误！未定义书签。

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iv © ISO #### 2026 – All rights reserved
iv
ISO/DTR 23583:(en)
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Formatted: Font: 11 pt, Bold
Foreword
Formatted: HeaderCentered, Left, Space After: 0 pt,
Line spacing: single
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Formatted: Default Paragraph Font
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.
Formatted: Font: Not Italic
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.htmlwww.iso.org/members.html.
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: FooterCentered, Left, Line spacing: single
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Left, Space
After: 0 pt, Line spacing: single
© ISO TR 23583 2026 – All rights reserved
v
ISO #####-#:####(X/DTR 23583:(en) Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold
Formatted: HeaderCentered, Left, Space After: 0 pt,
Introduction
Line spacing: single
Many factors affect the sulfur corrosion of copper windings in power equipment in the power industry. These
include:
— — temperature;
Formatted: List Continue 1
— — corrosive sulfide concentration in oil;
— — acid products derived from oil-paper insulation aging;
— — moisture;
— — the type of electric field (AC or DC electric field);
— — electric field strength;
— — the contact state between the copper winding and the insulating paper;
— — the quality of the copper winding.
These have a significant influence on the occurrence of sulfur corrosion and the generation of corrosion
products. Unfortunately, theThe current assessment methods of sulfur corrosion of copper windings do not
sufficiently consider these factors. Existing standards (e.g. ASTM D 1275A/B, ASTM D 1275B, IEC 62535, GB/T
Formatted: English (United Kingdom)
25961) test specifications or methods for testing whether the quality of insulating oil meets the requirements.
As for the corrosion of copper, the existing standards are test methods for the corrosion of copper metal in the
atmospheric environment, petroleum products, etc. Standards such as GB/T 38265.15, ASTM D 130 and ISO
6251specify6251 specify special testing or assessment methods for lubricants, oil and copper parts in
atmospheric environments (e.g. pipelines, tower parts and other structures), which does not fully apply to
power equipment.
Therefore, with reference to the existing standards for corrosive sulfur detection in insulating oil, this
document proposes a sulfur corrosion test method for copper winding in electric field for power equipment.
The method includes pre-treatment, model construction, the corrosion test method and corrosion level
judgments for copper windings.
This document contributes to controlling the quality of copper windings in electric power equipment,
reducing the failure of electric power equipment due to sulfur corrosion and prolonging the service life of
power equipment, which has great significance in improving the safe operation of power grids.
This document considers the effects of actual working conditions (e.g. electric field, the contact state between
th
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